The Big Bounce Theory

What was Before the Big Bang? An Identical, Reversed Universe

14 Apr , 2008 by

So what did exist before the Big Bang? This question would normally belong in the realms of deep philosophical thinking; the laws of physics have no right to probe beyond the Big Bang barrier. There can be no understanding of what was there before. We have no experience, no observational capability and no way of travelling back through it (we can’t even calculate it), so how can physicists even begin to think they can answer this question? Well, a new study of Loop Quantum Gravity (LQG) is challenging this view, perhaps there is a way of looking into the pre-Big Bang “universe”. And the conclusion? The Big Bang was more of a “Big Bounce”, and the pre-bounce universe had the same physics as our universe… just backwards… Confused? I am

LQG is a tough theory to put into words, but it basically addresses the problems associated with the incompatibilities behind quantum theory and general relativity, two crucial theories that characterize our universe. If these two theories are not compatible with each other, the search for the “Theory Of Everything” will be hindered, disallowing gravity to merge with the “Grand Unified Theory” (a.k.a. the electronuclear force). LQG quantizes gravity, thereby providing a possible explanation for gravity and a possible key to unlocking the Theory Of Everything. However, from the outset, LQG has many critics as there is little direct or indirect evidence backing up the theory.

See the previous Universe Today article on Loop Quantum Gravity»

Regardless, much work is being done into this area of research. The primary consequence to come from LQG is that it predicts that the Big Bang which occurred 13.7 billion years ago was actually a “Big Bounce”; our universe is therefore the product of a contracting universe before the Big Bang. The previous universe (or our universe “twin”) contracted to a single point (which could be interpreted as a “Big Crunch”) and then rebounded in a Big Bounce to produce the Big Bang as we’ve learned to accept as the birth of the universe as we know it. But until now, although the pre-bounce universe has been predicted, its characteristics could not be known. No information about the pre-bounce universe could be observed in today’s universe, the Big Bounce causes a “cosmic amnesia”, destroying all information of the previous universe.

Now, physicists Alejandro Corichi from Universidad Nacional Autónoma de México and Parampreet Singh from the Perimeter Institute for Theoretical Physics in Ontario are working on a simplified Loop Quantum Gravity (sLQG) theory where they approximate the value of the “quantum constraint”, a key equation in the LQG theory. What happens next is a little surprising. From their calculations, it would appear that a universe, identical to our own, with identical mechanics, existed before the Big Bounce.

…the twin universe will have the same laws of physics and, in particular, the same notion of time as in ours. The laws of physics will not change because the evolution is always unitary, which is the nicest way a quantum system can evolve. In our analogy, it will look identical to its twin when seen from afar; one could not distinguish them.” – Parampreet Singh

We are not talking about an alternate dimension; we are talking about an identical universe with the same space-time and quantum characteristics as our own. If we look at our universe now (13.7 billion years post-bounce), it would be identical to the universe 13.7 billion years before the Big Bounce. The only difference being the direction of time would be opposite; the pre-bounce universe would be reversed.

In the universe before the bounce, all the general features will be the same. It will follow the same dynamical equations, the Einstein’s equations when the universe is large. Our model predicts that this happens when the universe becomes of the order 100 times larger than the Planck size. Further, the matter content will be the same, and it will have the same evolution. Since the pre-bounce universe is contracting, it will look as if we were looking at ours backward in time.” – Parampreet Singh

Analysing what happened before the Big Bang is only part of the story. By making this approximation of a key LQG equation, Singh and Corichi are working on models where galaxies and other physical structures leave an imprint in the pre-bounce universe to influence the post-bounce universe. Would these structures be distributed in similar ways? Will the structures in one universe be similar or identical to structures in the other universe? There may also be an opportunity to look into the future of this universe and predict whether the conditions are right for another Big Bounce (once can imagine repeated bounces, producing a cycle of universes).

For now, this research is highly theoretical and any observational evidence will remain sparse for the time being. Although this is the case, it does begin to probe the big question and may push physics a bit closer toward describing what existed before the Big Bang…

Source: Physorg.com


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MrBill
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MrBill
April 14, 2008 6:21 PM

We’ll see………..

Jordan Lapp
Guest
April 14, 2008 5:54 PM

Wow, your bias is pretty evident. There’s about the same amount of evidence for LQG as there is for string theory… ie not much.

BlueAmberol
Member
BlueAmberol
April 14, 2008 6:07 PM

This makes much more sense than the notion that everything appeared all at once from nothing. Perhaps after many trillions(?) of years, our universe will expand to a maximum and then begin to contract.
13.7 billion years may be only a tiny fraction of a half cycle.

k98148
Guest
k98148
April 14, 2008 6:27 PM

No, ..we won’t see. (Refering to above) .. unless, you have discovered some form of immortality?

The Theory is very interesting and makes much more sense then suddenly there was a bang and all this material appeared out of nothingness.

Timber
Guest
Timber
April 14, 2008 6:33 PM

Wow, I hope I’m around another 80 years to follow this thought

zeb
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zeb
April 14, 2008 6:33 PM
For some reason, this reminds me of one of those conservation laws. If a particle at rest decays into several particles (say beta decay), they shoot off in different directions, but if you add up all their momentum, it is the same as the single particle at rest. Maybe it’s a “conservation of time” law, just one universe exploding in one temporal direction would violate the law, but two exploding universes would conserve the “time momentum” or whatever. Another thought: antimatter is mathmatically the time-reverse of regular matter (take a proton and run it backwards through time, it will behave like a normal anti-proton). Maybe this “twin universe” is made primarily of antimatter, further balancing out our matter-dominated… Read more »
Tom
Member
April 14, 2008 6:34 PM
@Dan Tillmanns: Actually I don’t think this makes any more or less sense than everything appearing “all at once from nothing”. Until we actually understand the nature of the singularity of Big Bang in real, physical terms, it’s all equally speculative. We understand that within out universe, matter/energy is conserved but not created from nothing, but that does not necessarily hold for beyond a state we do not yet understand, albeit in vague theoretical stabs. I look forwards to learning more about all this in the years to come and maybe we’ll understand these things within our life times. Maybe not. But, interesting though this for the imagination, it’s not more realistic that any other purely theoretical idea… Read more »
Dave
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Dave
April 14, 2008 7:49 PM

Our physicist friends are fielding “Curiouser and curiouser!” theories. Maybe in a few more paradigm shifts a moment of epiphany will show us that proof and faith are one in the same…

leafguy
Member
April 14, 2008 7:59 PM

The answer is 42

The Fool
Guest
April 14, 2008 8:04 PM

It would be helpful for the extremely long-term survival of our species if we could predict when and how the re-bounce, so to say, will happen so that we could prevent it.

The Fool

prot
Guest
prot
April 14, 2008 9:44 PM

See, I told you that the universe expands and collapses over and over, and that everything (including you, the other beings you cannibalize, and the Empire State Building) happen over and over.

bugzzz
Member
bugzzz
April 14, 2008 9:48 PM

An interesting idea, but even if there were a twin before our universe you still have the chicken/egg dilemma of how the very first universe (if there is such a thing) came to be.

Who made the maker(s)? Who baked the universal cake? smile

Lately I’m leaning towards the newer idea that our universe is essentially a virtual reality of a VR of a VR, etc. And I have less proof of this than I can shake a rolling pin at.

Yorrike
Guest
April 14, 2008 10:42 PM

Can someone please explain how time can “run backwards” ?

horrendous
Member
April 15, 2008 12:02 AM
In the mirror universe, humans are born from decomposing matter, worms excrete flesh onto bones, frail bodies rise from the ground, gradually increasing in strength and vigour,reaching a peak about 20 years before their death. They are eventually sucked into the body of thier mother, where they are absorbed for 9 months, until the father siphons out the essence. They eat excrement thru their arses, and excrete food thru their mouths, when it is taken to butchers shops and greengrocers to be made into animals and vegetables. And Mankind’s evolution began on myriad distant planets, eventually eventually leaving them and collecting together on Earth, gradually losing their technological skils and evolving into cavemen. “Little acorns from giant oaks… Read more »
Chris S
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Chris S
April 15, 2008 12:13 AM
My question is: How did beings in this Pre-Bounce universe percieve the passage of time? Did they percieve it as progressing forward while physics showed them as going backwards, which would indicate that we will be able to see it coming (as they would have) when matter begins to progress backwards. Or perhaps (I’m less fond of this one but it could be a possibility) they reached a critical point in technological advancement and all societies imploded in on themselves and destroyed each other? Or maybe they lived lives backwards; people came out of the ground and grew younger and younger until they had a surgery performed to put them in the womb. They could continue to regress… Read more »
mark lancaster
Guest
April 15, 2008 8:43 AM

yorrike: can someone please explain time?

Konstantine
Guest
Konstantine
April 15, 2008 2:39 AM

about the chicken egg dillemma :
My granma once told me:
“That is simple. The chicken came first, because if it was the egg that had come first no one would be there to sit on it so it would incubate.”
That’s all about. Keep an open mind and keep up the good work.
Answers are out there they just hang out with more questions.

TONY
Guest
TONY
April 15, 2008 3:13 AM

THERE WERE MANY BIG BANGS.
THAT’S THE PROBLEM, PEOPLE
DON’T WANT TO ACCEPT
ESPECIALLY THE CATHOLIC CHURCH.
THERE IS NO START OR END
LOCAL YES UNIVERSAL NO!

Simon
Guest
Simon
April 15, 2008 10:45 AM

If the Universe is cyclic, it seems to explain what the present Universe is expanding into, the ‘space’ vacated by the previous one. Perhaps there has never been a Universe Number ‘1’. Infinity may be the operational parameter in Universal cycles. Not a satisfactory ‘logical’ explanation but perhaps something to consider.

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